One of
the easiest ways to create or maintain interest in a song is to double one of
the musical parts. In traditional orchestration, the term “doubling” means to
assign a musical line or part to two or more instruments or instrumental
sections (such as violins or violas). In the recording studio “doubling” in most
cases means “double-tracking” – recording a second performance of a vocal or
instrumental part along with the first performance. The primary purpose of both
of these techniques is to make a part stand out by creating a thicker musical
texture. Because students in most labs cannot record their own audio tracks, the
techniques described in this article will focus on MIDI tracks.

Doubling
can be applied to any part in an arrangement – the melody, harmony, bass, and
even the percussion part. In
Example 1 the melody is played with a synthesizer
sound and centered in the stereo mix. In Measure 5 the melody is doubled using
the same sound but played one octave lower. You can hear how much bigger the
melody sounds with this octave doubling. The doubled part can be created either
by recording the part an octave lower onto a new track using the same sound or
by copying the original MIDI data, pasting it into a new track, and then
transposing the track down one octave. In Measure 9 the doubled track is
transposed two octaves down from the original track. In addition, the original
melody track is placed in the left speaker and the transposed melody is placed
in the right speaker. This placement creates an even bigger sound by adding a
dimension of width to the sound. (Note: the doubled MIDI track must be assigned
to a different MIDI channel for this to work. If both melody tracks are on the
same MIDI channel, any movement of either track’s pan control will affect both
tracks.)

In
Example 2 the harmony part is played by an acoustic guitar sample. This part was
played in real time and contains slight deviations in timing. One way to double
this part is to create a new track (assigned to the same guitar sound but on a
different MIDI channel) and simply play the part again. Playing the part a
second time is the best way to create the effect of two performers, because you
will have two different performances with slight variations in note start times,
durations, and velocities. This effect can be heard in Measures 5 – 8. (The
stereo effect is created by panning the two guitar tracks left and right.) In
Measure 9 the doubled track is detuned slightly to produce a thicker sound.

You can
sometimes use an editing technique to create the doubled part instead of
recording the part again. This technique can be very useful for students with
minimal keyboard skills. In this example you would begin by copying the original
guitar part to a new track and assigning the new track to a different MIDI
channel. Next, adjust the pan controls so that the original guitar part is
panned left and the copied track is panned right. To create the effect of two
guitarists, quantize the copied track to the nearest eighth-note. This will
create timing differences between the two tracks and it sound more like two
guitarists trying to play together.
Example 3 demonstrates this editing
technique. Measures 1-4 have the original guitar track panned center. Measures
5-8 add the copied, quantized part with the two parts panned left and right, and
Measures 9-12 add the detuning effect to the quantized guitar track. You can
hear that the sound produced by quantizing the copied track is very close to the
sound produced by recording the part a second time (as heard in Example 2).

Bass
parts aren’t usually doubled, but there are times when doubling the bass can
create an interesting texture. The first four measures of
Example 4 have the
bass part centered in the mix. In the next eight measures the bass part has been
doubled using the copy/quantize/pan technique used for the acoustic guitar in
Example 3. Notice how much larger the bass part sounds – we now get a sense of
ensemble (two players instead of one) and a sense of width (from panning one
track left and the other track right).

You can
hear how doubling can create a new texture in a mix without adding a new
instrumental sound. Doubling also makes it easy to produce a balanced stereo
mix, since you can have two performances of the same part using the same sound
panned left and right. Keep in mind that some instruments don’t always lend
themselves to this technique. Instruments such as the oboe, clarinet, flute,
solo violin (or any solo string instrument) best convey a sense of intimacy when
played solo and not doubled. In addition, doubling using identical samples of
these instruments can sometimes create phasing problems which can make the
samples sound more like organ stops instead of acoustic instruments. As always,
let your ear be your guide in telling you what parts need to be doubled to
improve a mix.